I haven't done side by side testing with decent looking H.264 footage (I've mostly just been messing with various ProRes formats here), but FCP X has a much more advanced rendering engine and supports ColorSync for display, so both of these things are plausible.

On the other hand, XDCAM EX material transferred in 7 has a weird pulsing color shift issue. It's subtle, but it's there.

I have not checked to see if it's there on export. Doing a full-screen viewer I could tell that the engine was taking some liberties with the sharpness of my footage, so it truly maybe a preview issue (something not unheard of in 7, either).

[Nate Weaver]"I have not checked to see if it's there on export. Doing a full-screen viewer I could tell that the engine was taking some liberties with the sharpness of my footage, so it truly maybe a preview issue (something not unheard of in 7, either)."

There's a preference to play back at high quality. (More likely to drop frames, of course.)